Micro-lattice Cross-flow Heat Exchangers for Aircraft

ABSTRACT

An aircraft micro-lattice cross-flow heat exchanger and methods are presented. A first aircraft fluid source inlet provides a first fluid from a first aircraft system, and a second aircraft fluid source inlet provides a second fluid from a second aircraft system. A structural body supports aviation induced structural loads and exchanges heat between the first fluid and the second fluid. The structural body comprises hollow channels forming two interpenetrating fluidically isolated volumes that flow the first fluid within the hollow channels and flow the second fluid external to the hollow channels isolated from the first fluid. The hollow channels comprise a hollow three-dimensional micro-truss comprising hollow truss elements extending along at least three directions, and hollow nodes interpenetrated by the hollow truss elements.

FIELD

Embodiments of the present disclosure relate generally to heatexchangers. More particularly, embodiments of the present disclosurerelate to aircraft heat exchangers.

BACKGROUND

Heat exchangers are used in various thermal management applications suchas heating, refrigeration, air conditioning, and in systems which createwaste heat such as power stations, chemical plants, and petroleumrefineries, and in conglomerations of systems, such as aircraft. A heatexchanger generally transfers heat from one medium to another. The mediamay be separated to never mix or may be in direct contact. Interfacepressure loss may represent a significant component consideration.Generally the rate of heat transfer is proportional to the heatexchanger size. Ongoing research is in part focused on development ofefficient heat exchanger systems that are light and small in size.

SUMMARY

An aircraft micro-lattice cross-flow heat exchanger and methods arepresented. A first aircraft fluid source inlet provides a first fluidfrom a first aircraft system, and a second aircraft fluid source inletprovides a second fluid from a second aircraft system. A structural bodysupports aviation induced structural loads and exchanges heat betweenthe first fluid and the second fluid. The structural body compriseshollow channels forming two interpenetrating fluidically isolatedvolumes that flow the first fluid within the hollow channels and flowthe second fluid external to the hollow channels isolated from the firstfluid. The hollow channels comprise a hollow three-dimensionalmicro-truss comprising hollow truss elements extending along at leastthree directions, and hollow nodes interpenetrated by the hollow trusselements.

In this manner, embodiments of the disclosure provide a heat exchangerthat also bears structural loads such as system pressures. The heatexchanger comprises enclosed fluid flow interfaces to a hollow porousmaterial that reduce discontinuities and sharp edges and consequentlyreduce flow disruptions, reduce pressure drops for fluid flowing intothe hollow porous material, and/or increases pressure recovery for fluidexiting the hollow porous material.

In an embodiment, a method for operating a micro-lattice cross-flow heatexchanger for an aircraft receives a first fluid in a first aircraftfluid source inlet from a first aircraft system, and receives a secondfluid in a second aircraft fluid source inlet from a second aircraftsystem. The method further supports an aviation structural load on astructural body forming two interpenetrating fluidically isolatedvolumes and comprising hollow channels comprising hollow truss elementswithin a hollow three-dimensional micro-truss. The hollowthree-dimensional micro-truss comprises hollow truss elements extendingalong at least three directions, and a plurality of hollow nodesinterpenetrated by the hollow truss elements. The method further flowsthe first fluid from the first aircraft fluid source inlet into thehollow channels through a first manifold comprising first openings intothe hollow channels. The method further flows the first fluid within thehollow channels, and flows the first fluid out of a second manifoldcomprising second openings from the hollow channels. The method furtherflows the second fluid external to the hollow channels and transfersheat between the first fluid flow and the second fluid flow via thestructural body.

In another embodiment, a micro-lattice cross-flow heat exchanger for anaircraft comprises a first aircraft fluid source inlet, a secondaircraft fluid source inlet, and a structural body. The first aircraftfluid source inlet provides a first fluid from a first aircraft system,and the second aircraft fluid source inlet provides a second fluid froma second aircraft system. The structural body supports aviation inducedstructural loads and exchanges heat between the first fluid and thesecond fluid. The structural body comprises hollow channels that formtwo interpenetrating fluidically isolated volumes configured to flow thefirst fluid within the hollow channels and flow the second fluidexternal to the hollow channels and isolated from the first fluid. Thehollow channels comprising a hollow three-dimensional micro-truss. Thehollow three-dimensional micro-truss comprises hollow truss elementsextending along at least three directions, and hollow nodesinterpenetrated by the hollow truss elements.

In a further embodiment, a method for configuring a micro-latticecross-flow heat exchanger for an aircraft configures a first aircraftfluid source inlet to receive a first fluid from a first aircraftsystem. The method further configures a second aircraft fluid sourceinlet to receive a second fluid from a second aircraft system. Themethod further configures hollow channels comprising hollow trusselements into a structural body comprising a hollow three-dimensionalmicro-truss forming two interpenetrating fluidically isolated volumesoperable for the first fluid to flow within the hollow channels and thesecond fluid to flow external to the hollow channels isolated from thefirst fluid. The method further configures first hollow truss elementsfrom among the hollow truss elements to extend along a first direction,and configures second hollow truss elements from among the hollow trusselements to extend along a second direction. The method furtherconfigures third hollow truss elements from among the hollow trusselements to extend along a third direction, and interpenetrates hollownodes by the hollow truss elements. The method further configures thestructural body to exchange heat between the first fluid and the secondfluid, and configures the structural body to support aviation inducedstructural loads.

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the detaileddescription. This summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

BRIEF DESCRIPTION OF DRAWINGS

A more complete understanding of embodiments of the present disclosuremay be derived by referring to the detailed description and claims whenconsidered in conjunction with the following figures, wherein likereference numbers refer to similar elements throughout the figures. Thefigures are provided to facilitate understanding of the disclosurewithout limiting the breadth, scope, scale, or applicability of thedisclosure. The drawings are not necessarily made to scale.

FIG. 1 is an illustration of a flow diagram of an exemplary aircraftproduction and service methodology.

FIG. 2 is an illustration of an exemplary block diagram of an aircraft.

FIG. 3 is an illustration of an exemplary micro-lattice cross-flow heatexchanger according to an embodiment of the disclosure.

FIG. 4 is an illustration of an expanded view of an exemplarymicro-lattice cross-flow heat exchanger showing hollow channels enteringand leaving hollow nodes according to an embodiment of the disclosure.

FIG. 5 is an illustration of an exemplary schematic of a micro-latticecross-flow heat exchanger according to an embodiment of the disclosure.

FIG. 6 is an illustration of an exemplary flowchart showing a processfor configuring micro-lattice cross-flow heat exchanger for an aircraftaccording to an embodiment of the disclosure.

FIG. 7 is an illustration of an exemplary flowchart showing a processfor operating a micro-lattice cross-flow heat exchanger for an aircraftaccording to an embodiment of the disclosure.

FIG. 8 is an illustration of an exemplary schematic of a micro-latticecross-flow heat exchanger comprising a heat pipe according to anembodiment of the disclosure.

FIG. 9 is an illustration of an exemplary schematic of a micro-latticecross-flow heat exchanger comprising a heat pipe according to anembodiment of the disclosure.

DETAILED DESCRIPTION

The following detailed description is exemplary in nature and is notintended to limit the disclosure or the application and uses of theembodiments of the disclosure. Descriptions of specific devices,techniques, and applications are provided only as examples.Modifications to the examples described herein will be readily apparentto those of ordinary skill in the art, and the general principlesdefined herein may be applied to other examples and applications withoutdeparting from the spirit and scope of the disclosure. Furthermore,there is no intention to be bound by any expressed or implied theorypresented in the preceding field, background, summary or the followingdetailed description. The present disclosure should be accorded scopeconsistent with the claims, and not limited to the examples describedand shown herein.

Embodiments of the disclosure may be described herein in terms offunctional and/or logical block components and various processing steps.It should be appreciated that such block components may be realized byany number of hardware, software, and/or firmware components configuredto perform the specified functions. For the sake of brevity,conventional techniques and components related to aircraft, aircraftcomponents, heat exchangers, fluid dynamics, and other functionalaspects of the systems (and the individual operating components of thesystems) may not be described in detail herein. In addition, thoseskilled in the art will appreciate that embodiments of the presentdisclosure may be practiced in conjunction with a variety of structuralbodies, and that the embodiments described herein are merely exampleembodiments of the disclosure.

Embodiments of the disclosure are described herein in the context ofsome non-limiting applications, namely, an air conditioning heatexchanger. Embodiments of the disclosure, however, are not limited tosuch air conditioning applications, and the techniques described hereinmay also be utilized in other applications. For example, embodiments maybe applicable to electronics cooling, battery cooling, liquid-liquidheat exchange, gas-liquid heat exchange, slurry-liquid heat exchange(e.g., slush hydrogen to liquid nitrogen), slurry-gas heat exchange,fuel-coolant heat exchange, Synergistic Air-Breathing Rocket Engines(SABRE), engine precoolers, engine oil coolers, hypersonic precoolers,intercoolers, hydraulic fluid heat exchangers, refrigeration heatexchangers, or other heat exchange applications.

As would be apparent to one of ordinary skill in the art after readingthis description, the following are examples and embodiments of thedisclosure and are not limited to operating in accordance with theseexamples. Other embodiments may be utilized and structural changes maybe made without departing from the scope of the exemplary embodiments ofthe present disclosure.

Embodiments provide a lightweight, high-performance cross-flowmicro-lattice heat exchanger structure for an aircraft, including air toair, liquid to liquid, and liquid to air heat transfer in both singleand two-phase flow. Embodiments use a hollow micro-lattice structure asa core structure in the micro-lattice heat exchanger structure forparticular applications. A fluid stream is passed through hollow tubescomprising the hollow micro-lattice structure. Another fluid streampasses around the hollow micro-lattice structure. This fluid passagemechanism permits transfer of heat between the two fluid streams withoutmixing the two fluids. The hollow micro-lattice structure is well-suitedfor use in multiple places on an aircraft where high heat transferbetween two fluid streams, low fluid pressure drop, low mass and lowvolume is desirable. For example, the micro-lattice heat-exchangerstructure may be used to transfer heat from compressed air stream to aRAM air stream, thus providing a source of cabin air at the propertemperature and pressure for passenger comfort.

Referring more particularly to the drawings, embodiments of thedisclosure may be described in the context of an exemplary aircraftmanufacturing and service method 100 (method 100) as shown in FIG. 1 andan aircraft 200 as shown in FIG. 2. During pre-production, the method100 may comprise specification and design 104 of the aircraft 200, andmaterial procurement 106. During production, component and subassemblymanufacturing 108 (process 108) and system integration 110 of theaircraft 200 takes place. Thereafter, the aircraft 200 may go throughcertification and delivery 112 in order to be placed in service 114.While in service by a customer, the aircraft 200 is scheduled forroutine maintenance and service 116 (which may also comprisemodification, reconfiguration, refurbishment, and so on).

Each of the processes of method 100 may be performed or carried out by asystem integrator, a third party, and/or an operator (e.g., a customer).For the purposes of this description, a system integrator may comprise,for example but without limitation, any number of aircraft manufacturersand major-system subcontractors; a third party may comprise, for examplebut without limitation, any number of vendors, subcontractors, andsuppliers; and an operator may comprise, for example but withoutlimitation, an airline, leasing company, military entity, serviceorganization; and the like.

As shown in FIG. 2, the aircraft 200 produced by the method 100 maycomprise an airframe 218 with a plurality of systems 220 and an interior222. Examples of high-level systems of the systems 220 comprise one ormore of a propulsion system 224, an electrical system 226, a hydraulicsystem 228, an environmental control system 230, and one or more heatexchanger systems 232. The one or more heat exchanger systems 232 may becontained in the airframe 218, the interior 222, the systems 220 such asthe propulsion system 224, the electrical system 226, the hydraulicsystem 228, and the environmental control system 230 or any system ofthe aircraft 200. Any number of other systems may also be included.Although an aerospace example is shown, the embodiments of thedisclosure may be applied to other industries.

It should not be inferred from FIG. 2 that an airplane comprises asingle, thermal management or, heat exchanger system that manages wasteheat from multiple systems. Rather, each system generally comprises oneor more heat exchangers to manage waste heat produced by its components.

Apparatus and methods embodied herein may be employed during any one ormore of the stages of the method 100. For example, components orsubassemblies corresponding to production of the process 108 may befabricated or manufactured in a manner similar to components orsubassemblies produced while the aircraft 200 is in service. Inaddition, one or more apparatus embodiments, method embodiments, or acombination thereof may be utilized during production stages of theprocess 108 and the system integration 110, for example, bysubstantially expediting assembly of or reducing the cost of an aircraft200. Similarly, one or more of apparatus embodiments, methodembodiments, or a combination thereof may be utilized while the aircraft200 is in service, for example and without limitation, to maintenanceand service 116.

FIG. 3 is an illustration of an exemplary micro-lattice cross-flow heatexchanger 300 according to an embodiment of the disclosure. Themicro-lattice cross-flow heat exchanger 300 may comprise a structuralbody 320, a manifold 306/322, and a plurality of hollow nodes 302/314.

The structural body 320 comprises a plurality of hollow channels 304/316configured to flow a first fluid 522 (FIG. 5) within the hollow channels304/316 and a second fluid 502 (FIG. 5) external to the hollow channels304/316.

In one embodiment, the hollow channels 304/316 may be a polymermicro-truss structure in a form of a regular hollow three-dimensionalmicro-truss of intersecting tubes, configured with hollow nodes 302/314at the intersections of the hollow channels 304/316, so that an interiorof each of the hollow channels 304/316 is in communication with anyother hollow channels 304/316 it intersects. The hollow channels 304/316comprise hollow truss elements within a hollow three-dimensionalmicro-truss comprising: first hollow truss elements 324 extending alonga first direction 330, second truss hollow truss elements 326 extendingalong a second direction 332, third truss hollow truss elements 328extending along a third direction 334.

The hollow channels 304/316 may comprise, for example but withoutlimitation, a cross-sectional shape that can be elliptical, circular,square, triangular, octagonal, star-shaped, a combination thereof, orother shape. Large aspect ratio elliptical shapes may improve heattransfer, and orientation of an ellipse's major axis may enhance heattransfer and enable better control of a pressure drop incurred by flowof the second fluid. In some embodiments, the hollow channels 304/316may comprise, for example but without limitation, one or more heat pipes800 (FIG. 8).

Access to an interior fluid volume, formed by connected interiors of thehollow channels 304/316, may be provided by an architected fluidinterface, which may also be referred to as a manifold such as themanifold 306/322, at each end of the structural body 320.

The manifold 306/322 is coupled to a first surface 512 and a secondsurface 518 (FIG. 5) of the structural body 320 respectively. Themanifold 306/322 each comprises a plurality of openings 308/310 into thehollow channels 304/316. A cross section (e.g., lateral, longitudinal,or other cross section) of each of the openings 308/310 may comprise,for example but without limitation, a tapered shape (e.g., for alongitudinal cross section), a polygon shape, quadrilateral shape, across-section of a hollow pyramid (e.g., for a lateral or longitudinalcross section), or other cross section configuration. The openings308/310 can be protruding or square-edged, or to reduce pressure dropincurred by the first flow, the openings can be radiused or tapered. Themanifold 306/322 may comprise a particulate filter 336. The particulatefilter 336 may be used to decrease a head loss coefficient of a flowencountering the openings 308/310.

Each of the hollow channels 304/316 that is at a surface such as thefirst surface 512 or the second surface 518 where a manifold 306/322 isplaced comprises an opening such as the openings 308/310, but some tubesegments of the hollow channels 304/316 may connect two nodes instead ofone node and one opening or, as illustrated in FIG. 3, into groups ofhollow channels 304/316. In the embodiment illustrated in FIG. 3, theopenings 308/310 may be in a form of a funnel or hollow pyramid, with adepth approximately or substantially equal to one half of the length, ina direction of a bore of the funnel, of a unit cell of the hollowthree-dimensional micro-truss of hollow channels 304/316.

Smooth transitions using the openings 308/310 shaped as described above(e.g., tapered etc.), at an interface between a bulk fluid and a hollowporous material such as the hollow channels 304/316 may result insignificantly lower pressure drop for a fluid flowing into the hollowchannels 304/316 and higher pressure recovery for a fluid exiting fromthe hollow channels 304/316 than manifolds having a flat surface with aflush hole for each hollow channels 304/316. In particular, a head losscoefficient of a flow encountering a right-angle inlet is approximately0.5, while the head loss coefficient for a filleted inlet is as low as0.04, representing an improvement of 12.5 times.

The hollow nodes 302/314 comprise locations at which the hollow channels304/316 interpenetrate.

FIG. 4 is an illustration of an expanded view 400 of an exemplarymicro-lattice cross-flow heat exchanger 300 showing hollow channelsentering and leaving hollow nodes according to an embodiment of thedisclosure. For example but without limitation, hollow nodes 404, 406,420, 434 and 446 comprise various configurations for flow of a fluid inthe direction 402. Hollow node 404 is interpenetrated by hollow trusselements 410, 414 and 418 bringing fluid into the hollow node 404, andby hollow truss elements 448, 452 and 456 receiving fluid from thehollow node 404. Hollow node 406 is interpenetrated by hollow trusselements 408, 412 and 424 bringing fluid into the hollow node 406, andby hollow elements 454, 458 and 460 receiving fluid from the hollow node406. Hollow node 420 is interpenetrated by hollow truss elements (notshown) bringing fluid into the hollow node 420, and by hollow trusselements 408, 418, 422 and 432 receiving fluid from the hollow node 420.Hollow node 434 is interpenetrated by hollow truss elements 422, 426 and430 bringing fluid into the hollow node 434, and by hollow trusselements 440, 442 and 444 receiving fluid from the hollow node 434. Node446 is interpenetrated by hollow truss elements 438, 444, 448 and 458bringing fluid into the hollow node 446, and by hollow elements (notshown) receiving fluid from the hollow node 446.

FIG. 5 is an illustration of an exemplary schematic of a micro-latticecross-flow heat exchanger 500 according to an embodiment of thedisclosure. The micro-lattice cross-flow heat exchanger 500 may comprisea structural body 514 (320 in FIG. 3), a first input manifold 524, afirst output manifold 534, a second input manifold 508, and a secondoutput manifold 526.

The first fluid 522 is flowed into the first input manifold 524 coupledto a surface 512 of the structural body 514. The structural body 514 isconfigured for the first fluid 522 to flow into and within a pluralityof hollow channels 546/544 (302/314 in FIG. 3). The structural body 514comprises a plurality of hollow nodes 516/530 (302/314 in FIG. 3) atwhich the hollow channels 546/544 interpenetrate. The first inputmanifold 524 and the first output manifold 534 comprise a plurality ofopenings 308/310 (see FIG. 3) into the hollow channels 546/544. Thefirst fluid 522 transfers heat to/from the structural body 514 and exitsthe first output manifold 534 as a first heat changed fluid 536.

The second fluid 502 is flowed into the second input manifold 508 aroundand external to the hollow channels 546/544. The second fluid 502transfers heat from/to the structural body 514 and exits the secondoutput manifold 526 as a second heat changed fluid 540. Thereby, heat istransferred between the first fluid 522 and the second fluid 502 via thestructural body 514.

In one embodiment, a first aircraft fluid source inlet 548 is configuredto provide a first fluid 522 from a first aircraft system 552. A secondaircraft fluid source inlet 504 is configured to provide a second fluid502 from a second aircraft system 554. The structural body 320/514 isconfigured to support aviation induced structural loads and exchangeheat between the first fluid 522 and the second fluid 502. The aviationinduced structural loads may comprise, for example but withoutlimitation, a proof and burst load, an air pressure cycling load, avibration load, an inertial load, a thermal cycling load, an airframestructural support load, a wing fairing bending load, a combinationthereof, an/or other aviation structural load.

The structural body 320/514 comprises a plurality of the hollow channels546/544 forming two interpenetrating fluidically isolated volumes andconfigured for flow of the first fluid 522 within the hollow channels546/544 and flow of the second fluid 502 external to the hollow channels546/544 isolated from the first fluid 522. The hollow channels 546/544comprise a hollow three-dimensional micro-truss such as themicro-lattice cross-flow heat exchanger 300/500 comprising hollow trusselements extending along at least three directions, and a plurality ofhollow nodes interpenetrated by the hollow truss elements as explainedabove.

The micro-lattice cross-flow heat exchanger 300/500 may be used in, forexample but without limitation, an aircraft nitrogen enriched aircooler, a power electronics cooler, a precooler, an air conditioningpack heat exchanger, an oil cooler, a refrigeration condenser, anevaporator exchanging heat between hot and cold refrigerant and air, ahydraulic fluid heat exchanger exchanging heat between hydraulic fluidand fuel or ram air, a liquid cooling system heat exchanger whichexchanges heat between liquid coolant and ram air, and other heatexchange application.

The first fluid 522 and the second fluid 502 may comprise, for examplebut without limitation, an aircraft engine bleed air, an aircraft RAMambient air, an aircraft nitrogen enriched air cooler, a recycledaircraft cabin air, a fanned heated air from a heat generating componenton an aircraft, a pumped aircraft engine oil, a pumped aircrafthydraulic oil, a pumped aircraft gearbox oil, a pumped aircraft liquidcoolant, a pumped aircraft refrigerant fluid, a vaporized fluid from aheat pipe, and other fluidic source.

In one embodiment, the micro-lattice cross-flow heat exchanger 500 mayuse engine bleed air as one fluid (first fluid) and engine fan air asthe other fluid (second fluid). This embodiment may be used as apre-cooler for an aircraft cabin air conditioning and temperaturecontrol system.

In another embodiment, the micro-lattice cross-flow heat exchanger 500may use compressed air (e.g., engine bleed air) as one fluid (firstfluid) and ambient (ram) air as the other fluid (second fluid). Thisembodiment may be used for the aircraft cabin air conditioning andtemperature control system.

In a further embodiment, the micro-lattice cross-flow heat exchanger 500may use compressed air (e.g., engine bleed air) as one fluid (firstfluid) and refrigerant as the other fluid (second fluid). Thisapplication is a subset of an air conditioning and temperature controlsystem of the aircraft cabin.

FIG. 6 is an illustration of an exemplary flowchart showing a process600 for configuring a micro-lattice cross-flow heat exchanger for anaircraft according to an embodiment of the disclosure. The various tasksperformed in connection with process 600 may be performed mechanically,by software, hardware, firmware, or any combination thereof. Forillustrative purposes, the following description of process 600 mayrefer to elements mentioned above in connection with FIGS. 1-5. In someembodiments, portions of the process 600 may be performed by differentelements of the micro-lattice cross-flow heat exchanger 300/500 such asthe structural body 320/514, the manifold 306/322, the hollow channels304/316, the hollow nodes 302/314, the first aircraft system 552, thesecond aircraft system 554, etc. Process 600 may have functions,material, and structures that are similar to the embodiments shown inFIGS. 1-4. Therefore common features, functions, and elements may not beredundantly described here.

Process 600 may begin by configuring a first aircraft fluid source inletto receive a first fluid from a first aircraft system (task 602).

Process 600 may continue by configuring a second aircraft fluid sourceinlet to receive a second fluid from a second aircraft system (task604).

Process 600 may continue by configuring a plurality of hollow channelscomprising hollow truss elements into a structural body comprising ahollow three-dimensional micro-truss forming two interpenetratingfluidically isolated volumes operable for the first fluid to flow withinthe hollow channels and the second fluid to flow external to the hollowchannels isolated from the first fluid (task 606).

Process 600 may continue by configuring a plurality of first hollowtruss elements from among the hollow truss elements to extend along afirst direction (task 608).

Process 600 may continue by configuring a plurality of second trusshollow truss elements from among the hollow truss elements to extendalong a second direction (task 610).

Process 600 may continue by configuring a plurality of third trusshollow truss elements from among the hollow truss elements to extendalong a third direction (task 612).

Process 600 may continue by interpenetrating a plurality of hollow nodesby the hollow channels (task 614).

Process 600 may continue by configuring the structural body to exchangeheat between the first fluid and the second fluid (task 616).

Process 600 may continue by configuring the structural body to supportaviation induced structural loads (task 618).

Process 600 may continue by coupling a first manifold comprising aplurality of first openings to the first aircraft fluid source inlet anda first surface of the structural body (task 620).

Process 600 may continue by coupling the first openings to the hollowchannels (task 622).

Process 600 may continue by coupling a second manifold comprising aplurality of second openings to the second aircraft fluid source inletand a second surface of the structural body (task 624).

Process 600 may continue by coupling the second openings to the hollowchannels (task 626).

Process 600 may continue by configuring a cross section (e.g., lateral,longitudinal, or other cross section) of each of the openings tocomprise a tapered opening, a polygon, a quadrilateral, a cross sectionof a hollow pyramid, or a combination thereof (task 628).

A process of forming a hollow porous material such as the hollowchannels 304/316 into the structural body 320 is described in U.S. Pat.No. 7,653,276 content of which is incorporated by reference herein inits entirety.

FIG. 7 is an illustration of an exemplary flowchart showing a processfor operating a micro-lattice cross-flow heat exchanger for an aircraftaccording to an embodiment of the disclosure. The various tasksperformed in connection with process 700 may be performed mechanically,by software, hardware, firmware, or any combination thereof. Forillustrative purposes, the following description of process 700 mayrefer to elements mentioned above in connection with FIGS. 1-4. In someembodiments, portions of the process 700 may be performed by differentelements of the micro-lattice cross-flow heat exchanger 300/400 such asthe structural body 320/514, the manifold 306/322, the hollow channels304/316, the hollow nodes 302/314, the first aircraft system 552, thesecond aircraft system 554, etc. Process 700 may have functions,material, and structures that are similar to the embodiments shown inFIGS. 1-4. Therefore common features, functions, and elements may not beredundantly described here.

Process 700 may begin by receiving a first fluid in a first aircraftfluid source inlet from a first aircraft system (task 702).

Process 700 may continue receiving a second fluid in a second aircraftfluid source inlet from a second aircraft system (task 704).

Process 700 may continue by supporting an aviation structural load on astructural body forming two interpenetrating fluidically isolatedvolumes and comprising a plurality of hollow channels comprising ahollow three-dimensional micro-truss comprising a plurality of hollowtruss elements extending along at least three directions, and aplurality of hollow nodes interpenetrated by the hollow truss elements(task 706).

Process 700 may continue by flowing the first fluid from the firstaircraft fluid source inlet into the hollow channels through a firstmanifold comprising a plurality of first openings into the hollowchannels (task 708).

Process 700 may continue by flowing the first fluid within the hollowchannels (task 710).

Process 700 may continue by flowing the first fluid out of a secondmanifold comprising a plurality of second openings from the hollowchannels (task 712).

Process 700 may continue by flowing the second fluid from the secondaircraft fluid source inlet external to the hollow channels (task 714).

Process 700 may continue by transferring heat between the first fluidflow and the second fluid flow via the structural body (task 716).

Process 700 may continue by inducing the first fluid flow from enginebleed air and the second fluid flow from engine fan air (task 718).

Process 700 may continue by using the micro-lattice cross-flow heatexchanger in an aircraft cabin air conditioning and temperature controlsystem, wherein the aviation structural load comprises a wing fairingbending load (task 720).

Process 700 may continue by inducing the first fluid flow from enginebleed air and the second fluid flow from ram air (task 722).

Process 700 may continue by using the micro-lattice cross-flow heatexchanger in an aircraft cabin air conditioning and temperature controlsystem, wherein the aviation structural load comprises a wing fairingbending load (task 724).

Process 700 may continue by inducing the first fluid flow from enginebleed air, wherein the second fluid flow comprises a refrigerant (task726). The refrigerant may comprise, for example but without limitation,Freon, Freon replacements (e.g., R134a), water, chlorofluorocarbons, ramair, fan air, or other refrigerant.

Process 700 may continue by using the micro-lattice cross-flow heatexchanger in an aircraft cabin air conditioning and temperature controlsystem, wherein the aviation structural load comprises a proof and burstload, and a pressure cycle load (task 728).

Process 700 may continue by inducing the first fluid flow from engineoil, wherein the second fluid flow comprises fan air (task 730).

Process 700 may continue by using the micro-lattice cross-flow heatexchanger in an oil cooling system, wherein the aviation structural loadcomprises a proof and burst load, a pressure cycle load, and a vibrationload (task 732).

Process 700 may continue by inducing the first fluid flow from hydraulicfluid, wherein the second fluid flow comprises fuel or ram air (task734).

Process 700 may continue by using the micro-lattice cross-flow heatexchanger in an oil cooling system, wherein the aviation structural loadcomprises a proof and burst load, a pressure cycle load, and a vibrationload (task 736).

Process 700 may continue by inducing the first fluid flow and the secondfluid flow from an aircraft engine bleed air, an aircraft RAM ambientair, an aircraft nitrogen enriched air cooler, a recycled aircraft cabinair, a fanned heated air from a heat generating component on anaircraft, a pumped aircraft engine oil, a pumped aircraft hydraulicfluid, a pumped aircraft gearbox oil, a pumped aircraft liquid coolant,and a pumped aircraft refrigerant fluid, or a combination thereof (task738).

Process 700 may continue by using the micro-lattice cross-flow heatexchanger in an aircraft nitrogen enriched air cooler, a powerelectronics cooler, a precooler, an air conditioning pack heatexchanger, an oil cooler. a refrigeration condenser, an evaporatorexchanging heat between hot and cold refrigerant and air, a hydraulicfluid heat exchanger exchanging heat between hydraulic fluid and fuel orram air, a liquid cooling system heat exchanger which exchanges heatbetween liquid coolant and ram air, or a combination thereof (task 740).

FIG. 8 is an illustration of an end view 806, a section A-A view 802,and a section B-B view 804 of an exemplary schematic of a micro-latticecross-flow heat exchanger 800 (heat pipe 800) according to an embodimentof the disclosure. The micro-lattice cross-flow heat exchanger 800comprises a heat pipe configuration, thus the micro-lattice cross-flowheat exchanger 800 and the heat pipe 800 may be used interchangeably inthis document. The micro-lattice cross-flow heat exchanger 800 maycomprise a micro-truss structural body 812 (320/514 in FIGS. 3 and 5)comprising the hollow channels 304/316/546/544 (FIGS. 3 and 5). The heatpipe 800 may comprise, for example, a 2-sided heat pipe interconnectedby the micro-truss structural body 812. The micro-truss structural body812 functions as a condenser for a heat pipe fluid (not shown) withinthe micro-truss structural body 812 that is vaporized at sides 828/830that are exposed to a heat load (flux) 832/834 respectively. The heatpipe fluid of the heat pipe 800 may comprise, for example but withoutlimitation, water, Freon, a hydrocarbon, an ionic liquid, or otherfluid.

Each side 824/826/828/830 of the micro-lattice cross-flow heat exchanger800 comprises a wick structure 816/818/820/822 respectively. The wickstructure 816/818/820/822 may be configured on a subset of the sides824/826/828/830 such as, but without limitation, all of the sides824/826/828/830, three sides among the sides 824/826/828/830, a singleside among the sides 824/826/828/830, or other configuration. In someembodiments, a laterally oriented wick structure in all adjacent four ofthe sides 824/826/828/830 provide return paths of condensed fluid backto a hot spot on one or more of the sides 824/826/828/830. In variousembodiments, the wick structure 816/818/820/822 may comprise, forexample but without limitation, a longitudinally oriented wickstructure, a laterally oriented wick structure, an omni-directionallyoriented wick structure, or other wick structure.

In some embodiments, a cooling fluid 808 enters a first side 836 of themicro-lattice cross-flow heat exchanger 800 and flows through and aroundan exterior 814 of the micro-truss structural body 812. The coolingfluid 808 may exit a second side 838 of the micro-lattice cross-flowheat exchanger 800.

Heat applied to any area of the sides 824/826/828/830 of themicro-lattice cross-flow heat exchanger 800 results in the heat pipefluid evaporating from point(s) of exposure and a vapor of the heat pipefluid migrating into the hollow channels 304/316 (FIG. 3) of themicro-truss structural body 812 in closest proximity to the point(s) ofexposure. A flow of the cooling fluid 808 through and around theexterior 814 of the micro-truss structural body 812 then absorbs heatfrom the vapor of the heat pipe fluid and causes it to condense to acondensed refrigerant. The condensed refrigerant flows through themicro-truss structural body 812 (e.g., guided by gravity) to the wickstructure 816/818/820/822 in a lowest of the sides 824/826/828/830.Capillary action in the wick structure 816/818/820/822 then guides thecondensed refrigerant back to the hot spot, where the cycle beginsagain.

In an embodiment, the first aircraft system 552 comprises a heat pipesurface (not shown) operable to vaporize the heat pipe fluid in responseto heating of the heat pipe surface to provide the vaporized heat pipefluid.

FIG. 9 is an illustration of an end view, a section A-A view, and asection B-B view of an exemplary schematic of a micro-lattice cross-flowheat exchanger 900 comprising a heat pipe configuration according to anembodiment of the disclosure. The micro-lattice cross-flow heatexchanger 900 may comprise various cross-section shape configurations ofa flow body 912 such as, but without limitation, circles, ellipses,triangles, pentagons, polygons, variable cross-sections along theirlengths, or a combination thereof. A surface 916 of the micro-latticecross-flow heat exchanger 900 absorbs a heat flux 914. The micro-latticecross-flow heat exchanger 900 comprises longitudinal and lateral wickstructures 904, and a hollow micro-truss structure 902 occupies a centerof the micro-lattice cross-flow heat exchanger 900.

A cooling fluid 908 enters the micro-lattice cross-flow heat exchanger900 through a coolant inlet 906 and flows through and around an exteriorof the hollow micro-truss structure 902. The cooling fluid 908 absorbsheat from the hollow micro-truss structure 902 and a vaporized heat pipefluid (not shown). Thereby, the hollow micro-truss structure 902 servesas a condenser to condense the vaporized heat pipe fluid into acondensed refrigerant (not shown). The wick structures 904 transport thecondensed refrigerant from the hollow micro-truss structure 902 back tothe wick structures 904 and back to a heated area, thereby enablingcontinuous evaporation and, in effect, management of a heat load.

In this manner, embodiments of the disclosure provide a cost-effectivefluid flow interface to a hollow porous material, which reducesdiscontinuities and sharp edges and consequently reduces flowdisruption, reduces pressure drop for fluid flowing into the hollowporous material, and/or increases pressure recovery for fluid exitingthe hollow porous material.

While at least one example embodiment has been presented in theforegoing detailed description, it should be appreciated that a vastnumber of variations exist. It should also be appreciated that theexample embodiment or embodiments described herein are not intended tolimit the scope, applicability, or configuration of the subject matterin any way. Rather, the foregoing detailed description will providethose skilled in the art with a convenient road map for implementing thedescribed embodiment or embodiments. It should be understood thatvarious changes can be made in the function and arrangement of elementswithout departing from the scope defined by the claims, which includesknown equivalents and foreseeable equivalents at the time of filing thispatent application.

The above description refers to elements or nodes or features being“connected” or “coupled” together. As used herein, unless expresslystated otherwise, “connected” means that one element/node/feature isdirectly joined to (or directly communicates with) anotherelement/node/feature, and not necessarily mechanically. Likewise, unlessexpressly stated otherwise, “coupled” means that oneelement/node/feature is directly or indirectly joined to (or directly orindirectly communicates with) another element/node/feature, and notnecessarily mechanically. Thus, although FIGS. 1-5 depict examplearrangements of elements, additional intervening elements, devices,features, or components may be present in an embodiment of thedisclosure.

Terms and phrases used in this document, and variations thereof, unlessotherwise expressly stated, should be construed as open ended as opposedto limiting. As examples of the foregoing: the term “including” shouldbe read as meaning “including, without limitation” or the like; the term“example” is used to provide exemplary instances of the item indiscussion, not an exhaustive or limiting list thereof; and adjectivessuch as “conventional,” “traditional,” “normal,” “standard,” “known” andterms of similar meaning should not be construed as limiting the itemdescribed to a given time period or to an item available as of a giventime, but instead should be read to encompass conventional, traditional,normal, or standard technologies that may be available or known now orat any time in the future. Likewise, a group of items linked with theconjunction “and” should not be read as requiring that each and everyone of those items be present in the grouping, but rather should be readas “and/or” unless expressly stated otherwise. Similarly, a group ofitems linked with the conjunction “or” should not be read as requiringmutual exclusivity among that group, but rather should also be read as“and/or” unless expressly stated otherwise.

Furthermore, although items, elements or components of the disclosuremay be described or claimed in the singular, the plural is contemplatedto be within the scope thereof unless limitation to the singular isexplicitly stated. The presence of broadening words and phrases such as“one or more,” “at least,” “but not limited to” or other like phrases insome instances shall not be read to mean that the narrower case isintended or required in instances where such broadening phrases may beabsent.

1. A method for operating a micro-lattice cross-flow heat exchanger foran aircraft, the method comprising: receiving a first fluid in a firstaircraft fluid source inlet from a first aircraft system; receiving asecond fluid in a second aircraft fluid source inlet from a secondaircraft system; supporting an aviation induced structural load on astructural body forming two interpenetrating fluidically isolatedvolumes and comprising a plurality of hollow channels comprising ahollow three-dimensional micro-truss comprising a plurality of hollowtruss elements extending along at least three directions, and aplurality of hollow nodes interpenetrated by the hollow truss elements;flowing the first fluid from the first aircraft fluid source inlet intothe hollow channels through a first manifold comprising a plurality offirst openings into the hollow channels; flowing the first fluid withinthe hollow channels; flowing the first fluid out of a second manifoldcomprising a plurality of second openings from the hollow channels;flowing the second fluid from the second aircraft fluid source inletexternal to the hollow channels; and transferring heat between the firstfluid and the second fluid via the structural body.
 2. The method ofclaim 1, wherein the aviation structural load comprises a proof andburst load, an air pressure cycling load, a vibration load, an airframestructural support load, an inertial load, a thermal cycling load, or acombination thereof.
 3. The method of claim 1, further comprising:inducing the first fluid from engine bleed air and the second fluid fromengine fan air; and using the micro-lattice cross-flow heat exchanger asa pre-cooler in an aircraft cabin air conditioning and temperaturecontrol system, wherein the aviation structural load comprises a wingfairing bending load.
 4. The method of claim 1, further comprising:inducing the first fluid from engine bleed air and the second fluid fromram air; and using the micro-lattice cross-flow heat exchanger in anaircraft cabin air conditioning and temperature control system, whereinthe aviation structural load comprises a wing fairing bending load. 5.The method of claim 1, further comprising: inducing the first fluid fromengine bleed air, wherein the second fluid comprises a refrigerant; andusing the micro-lattice cross-flow heat exchanger in an aircraft cabinair conditioning and temperature control system, wherein the aviationstructural load comprises a proof and burst load, and a pressure cycleload.
 6. The method of claim 1, further comprising: inducing the firstfluid from engine oil, wherein the second fluid comprises fan air; andusing the micro-lattice cross-flow heat exchanger in an oil coolingsystem, wherein the aviation structural load comprises a proof and burstload, a pressure cycle load, and a vibration load.
 7. The method ofclaim 1, further comprising: inducing the first fluid from hydraulicfluid, wherein the second fluid comprises fuel or ram air; and using themicro-lattice cross-flow heat exchanger in an oil cooling system,wherein the aviation structural load comprises a proof and burst load, apressure cycle load, a vibration load, or a combination thereof.
 8. Themethod of claim 1, further comprising inducing the first fluid and thesecond fluid from an aircraft engine bleed air, an aircraft RAM ambientair, an aircraft nitrogen enriched air cooler, a recycled aircraft cabinair, a fanned heated air from a heat generating component on anaircraft, a vaporized fluid from a heat pipe, a pumped aircraft engineoil, a pumped aircraft hydraulic fluid, a pumped aircraft gearbox oil, apumped aircraft liquid coolant, a pumped aircraft refrigerant fluid, acoolant, or a combination thereof.
 9. The method for claim 1, furthercomprising using the micro-lattice cross-flow heat exchanger in anaircraft nitrogen enriched air cooler, an electronics cooler, aprecooler, an air conditioning pack heat exchanger, an oil cooler. arefrigeration condenser, an evaporator exchanging heat between hot andcold refrigerant and air, a hydraulic fluid heat exchanger exchangingheat between hydraulic fluid and fuel or ram air, a liquid coolingsystem heat exchanger which exchanges heat between liquid coolant andram air, or a combination thereof.
 10. A micro-lattice cross-flow heatexchanger for an aircraft, comprising: a first aircraft fluid sourceinlet operable to provide a first fluid from a first aircraft system; asecond aircraft fluid source inlet operable to provide a second fluidfrom a second aircraft system; and a structural body operable to supportaviation induced structural loads and exchange heat between the firstfluid and the second fluid, and comprising a plurality of hollowchannels forming two interpenetrating fluidically isolated volumes andoperable for flow of the first fluid within the hollow channels and flowof the second fluid external to the hollow channels isolated from thefirst fluid, the hollow channels comprising a hollow three-dimensionalmicro-truss comprising a plurality of hollow truss elements extendingalong at least three directions, and a plurality of hollow nodesinterpenetrated by the hollow truss elements.
 11. The micro-latticecross-flow heat exchanger of claim 10, wherein the aviation inducedstructural loads comprise proof and burst, air pressure cycling,vibration, airframe structural support, an inertial load, a thermalcycling load, or a combination thereof.
 12. The micro-lattice cross-flowheat exchanger of claim 10, further comprising: a first manifold coupledto the first aircraft fluid source inlet and a first surface of thestructural body, and comprising a plurality of first openings into thehollow channels; and a second manifold coupled to the second aircraftfluid source inlet and a second surface of the structural body, andcomprising a plurality of second openings into the hollow channels. 13.The micro-lattice cross-flow heat exchanger of claim 12, wherein thefirst manifold and the second manifold further comprise a particulatefilter.
 14. The micro-lattice cross-flow heat exchanger of claim 12,wherein a cross section of each of the first openings and the secondopenings comprises a tapered opening, a polygon, a quadrilateral, across section of a hollow pyramid, or a combination thereof.
 15. Themicro-lattice cross-flow heat exchanger of claim 10, wherein the firstfluid and the second fluid are induced from an aircraft engine bleedair, an aircraft RAM ambient air, an aircraft nitrogen enriched aircooler, a recycled aircraft cabin air, a fan heated air from a heatgenerating component on an aircraft, a vaporized fluid from a heat pipe,a pumped aircraft engine oil, a pumped aircraft hydraulic fluid, apumped aircraft gearbox oil, a pumped aircraft liquid coolant, a pumpedaircraft refrigerant fluid, a coolant, or a combination thereof.
 16. Themicro-lattice cross-flow heat exchanger of claim 10, wherein: the firstfluid comprises a vaporized heat pipe fluid; the second fluid comprisesa cooling fluid; the first aircraft fluid source inlet comprises a wickstructure operable to retain the heat pipe fluid; and the first aircraftsystem comprises a heat pipe surface operable to vaporize the heat pipefluid in response to heating of the heat pipe surface to provide thevaporized heat pipe fluid.
 17. The micro-lattice cross-flow heatexchanger of claim 16, wherein the wick structure comprises, alongitudinally oriented wick structure, a laterally oriented wickstructure, an omni-directionally oriented wick structure, or acombination thereof.
 18. A method for configuring a micro-latticecross-flow heat exchanger for an aircraft, the method comprising:configuring a first aircraft fluid source inlet to receive a first fluidfrom a first aircraft system; configuring a second aircraft fluid sourceinlet to receive a second fluid from a second aircraft system;configuring a plurality of hollow channels comprising hollow trusselements into a structural body comprising a hollow three-dimensionalmicro-truss forming two interpenetrating fluidically isolated volumesoperable for the first fluid to flow within the hollow channels and thesecond fluid to flow external to the hollow channels isolated from thefirst fluid; configuring a plurality of first hollow truss elements fromamong the hollow truss elements to extend along a first direction;configuring a plurality of second truss hollow truss elements from amongthe hollow truss elements to extend along a second direction; andconfiguring a plurality of third truss hollow truss elements from amongthe hollow truss elements to extend along a third direction;interpenetrating a plurality of hollow nodes by the hollow trusselements; configuring the structural body to exchange heat between thefirst fluid and the second fluid; and configuring the structural body tosupport aviation induced structural loads.
 19. The method of claim 18,wherein the aviation induced structural loads comprise: a proof andburst load, an air pressure cycling load, a vibration load, an airframestructural support load, or a combination thereof.
 20. The method ofclaim 18, further comprising: coupling a first manifold comprising aplurality of first openings to the first aircraft fluid source inlet anda first surface of the structural body; and coupling the first openingsto the hollow channels.
 21. The method of claim 20, further comprising:coupling a second manifold comprising a plurality of second openings tothe second aircraft fluid source inlet and a second surface of thestructural body; and coupling the second openings to the hollowchannels.
 22. The method of claim 21, further comprising configuring across section of each of the first openings and the second openings tocomprise a tapered opening, a polygon, a quadrilateral, a cross sectionof a hollow pyramid, or a combination thereof.